The latest tensions over North Korea's nuclear weapons program is playing out in a maritime vigil being kept in waters west of the Korean peninsula. A handful of tiny South Korean islands are inhabited mainly by aging fishermen and their families- but also by South Korean military personnel ready to respond to any incursion by the North. VOA headed out to the islands, which North Korea mentioned by name in a recent warning to the United States and South Korea.

Waves lap the shore of South Korea's Yeonpyeong Island- creating a hypnotic lullaby in this sleepy fishing community.

Around here, the month of June is the high season of the year for catching blue crabs, a delicacy that fetches a handsome price in restaurants on the Korean mainland.

But South Korean coast guard boats patrolling these waters have noticed an ominous sign in recent weeks. Senior Officer Kim Yong-sun says the swarm of Chinese fishing boats that usually show up each year are staying away. "Usually lots of Chinese boats cross over to this area to fish, but due to North Korea's threats, they aren't coming," he said. "We saw two or three of them yesterday- today there were none."

Chinese boats also disappeared just before two deadly naval battles in waters near Yeonpyeong - one in 1999 and another in 2002.

Yeonpyeong is only about 11 kilometers from North Korean territory - and even closer to a United Nations-designated maritime border with the North that Pyongyang has never recognized.

As tensions escalated over North Korea's recent nuclear weapons test, Pyongyang warned it could not "guarantee the safety" of U.S. or South Korean boats near Yeonpyeong or a handful of other nearby islands.

Out at sea, large South Korean navy ships are visible - reminders that Seoul has deployed some of its most advanced seafaring weaponry to deter North Korea from any provocations.

South Korean marines also keep a constant watch, from observation posts - on nearby Baekryung island - where North Korean territory is visible across a relatively small patch of water.

Past South Korean administrations have downplayed West Sea tensions in an attempt to engage North Korea.

However, the administration of current President Lee Myung Bak has vowed to back up the South's navy with advanced warplanes in retaliation for any attack. Rules of engagement have also been updated to allow South Korean forces to strike at the North's land-based artillery positions if they are used to attack the South's ships.

As for the fishermen- many remember the past naval battles, but say life here goes on as normal.

"We're not that tense actually. We've been through this all before so we're used to it," one fisherman said.

"Missiles are expensive. North Korea won't waste them shooting at this place. They will aim them at big cities, like Seoul. All that matters to us here is whether we can fish - and how much we have to compete with those Chinese fishing boats," another fisherman states.

A North Korean patrol boat crossed briefly into South Korean waters this month, and was turned back. So far, there have been no other incidents.